1. Field of present exemplary embodiments
The present exemplary embodiments relate to an inclination calculation apparatus and an inclination calculation program, and more specifically to an inclination calculation apparatus and an inclination calculation program for calculating an inclination of an input device using an output from acceleration detection means included in the input device.
2. Description of Background Art
Conventionally, technologies for calculating an inclination of a device including acceleration detection means have been proposed. For example, patent document 1 (Japanese Laid-Open Patent Publication No. 2001-159951) describes an information processing device including acceleration detection means. In this information processing device, an inclination of the device is calculated from an acceleration detected by the acceleration detection means (an angle of the device with respect to a direction of gravity), and an operation command is generated using the calculated inclination. According to such a method for calculating an inclination of a device using the acceleration detection means, the inclination of the device is calculated by calculating the direction of an acceleration of gravity detected by the acceleration detection means.
However, the technology described in patent document 1 has a problem in that since the inclination of the input device is calculated only from the detected acceleration, the detected inclination may not be correct. When, for example, the device is being moved by the user or being vibrated by the destabilization of the user's hand, the detected acceleration includes acceleration components caused by an inertial force in addition to the acceleration of gravity. Therefore, the direction of the detected acceleration is offset from the direction of the acceleration of gravity. As a result, an accurate inclination cannot be calculated.
According to the technology described in patent document 1, processing for correcting the inclination so as to be as close as possible to the accurate value is executed; for example, a low-frequency component is extracted from the detected acceleration. However, even with such processing, a method of using only the acceleration has a limit in terms of the accuracy of the calculated inclination. When processing for correcting the inclination is executed, there occurs another problem in that the calculation of the inclination is delayed with respect to the detection of the acceleration.